Gorilla Glue

skidesmond · Post by **skidesmond** » Mon Feb 28, 2011 12:29 pm

( I moved the original post to here )

I pressed a pair of skis for a friend today (hope they turnout well). Then I got bored while the skis were being pressed.

I did some experiments today using gorilla glue as an alternative to epoxy. One short coming is that it has a shorter working time than epoxy (depending on what you are using). I decided to pursue this idea after I made the all wood ski using Gorilla Glue. I have no doubt it is durable and water proof. The glue is water proof.

I glued up a 3 samples today.

1. p-tex base with edges, VDS, and a poplar wood veneer.
2. p-tex with edges, 20oz FG and poplar wood veneer (no vds).
3. poplar and Formica

Samples 1 and 2 seemed to form a very strong bond and still be flexible. Sample 2 was much firmer because of the FG. In all the samples I dampened the materials with water, even the FG, and applied the Gorilla glue. I warmed the glue up using a heat lamp and it flowed and wetted out just like epoxy.

When I made the all wood ski I used less than 8oz of glue for both skis. That's a fairly sizable savings versus epoxy. One gallon epoxy/hardener delivered from QCM runs about $110. I can make 4-5 skis with epoxy, that's $22-$28 for a pair of skis. The Gorilla glue is $11 for 8oz from the local hardware store. Granted when I made the all wood ski I didn't use FG but I think a fair amount of savings can be found using Gorilla Glue.

It takes a little more time to wet out FG using glue than wetting out veneer with glue. But I think with careful planning and quick hands this maybe a viable alternative to epoxy and save a few bucks too.

As for the Formica.... I was able to bond wood to Formica. However I was able to break the sample Formica and the edge of Formica was extremely sharp. I think Formica could work in a ski lay up as a top sheet. It will add rigidity to the ski/board so that needs to be factored in to the design. And Formica, such as a granite Formica would look pretty cool on the mtn. But if it should crack or break it leaves a very sharp edge, and could be dangerous.

That's it for now. I'll post some pics tomorrow.

Other posts about Gorilla Glue
http://www.skibuilders.com/phpBB2/viewt ... rilla+glue

skidesmond · Post by **skidesmond** » Mon Feb 28, 2011 2:21 pm

Here's photos of the Gorilla Glue experiment:

Sample 1: Ptex, VDS, metal edge, 1/16in veneer. Very strong bond. Hard to separate materials even with a chisel.

Sample 2; Ptex, Metal Edge, FG, 1/16in veneer. Very strong bond. Hard to separate materials even with a chisel. You can see how the veneer broke when tried to pry it apart.

Broke the bond only when I applied a chisel to it.

Sample 3: Formica and wood veneer. Tried this for grins. Would still like to use a Formica top sheet but seems fairly dangerous with sharp edge where it snapped. That could do some damage to you if a ski or board broke like that.

I think I see a ski in the works using Gorilla glue instead of epoxy. The all wood ski was done with Gorilla Glue after the epoxy bond failed. I wish I had put a P-tex base on it now.

Any one else have experience using this glue in the layup? I'm going too see if I have enough material on hand. If so, I'll give it try before the season is over.

tufty · Post by **tufty** » Sun Mar 06, 2011 1:13 pm

I'm interested. Have you done any testing wrt durability (repeated flexing until failure, etc)?

skidesmond · Post by **skidesmond** » Sun Mar 06, 2011 1:52 pm

Not really, other than just bending by hand 20-30 times. I need to make some samples w/o edges because the sample pieces don't really bend that easy. It seems pretty durable. Their website says it's not suitable on polyethylene plastics. But I know some folks are using it to bond sidewalls.

It seems to be bonding the p-tex, metal edges, FG and wood ok. I'm planning on making a ski w/ this layup:

Ptex, edges, VDS, FG, core, 1/16 poplar veneer, 1/16 ash veneer. Or re-make the "Going Old school all wood ski" w/ a ptex base instead of the wood base.

Would like to get this done before the end of the season.

http://en.wikipedia.org/wiki/Polyethylene

http://www.gorillaglue.com/glues/glue-guide.aspx

vinman · Post by **vinman** » Sun Mar 06, 2011 2:54 pm

P-tex is polyethelene as in uhmwPE, but it seems that if it is abraded and flame treated it will bond.

skidesmond · Post by **skidesmond** » Sun Mar 06, 2011 3:22 pm

Thanks Vinman. I was pretty sure PE and UHMWPE were in the same family of plastics. It seems to bond fine.

tufty · Post by **tufty** » Sun Mar 06, 2011 11:38 pm

The problem with (UHMW)PE and other polyolefins (including polypropylene and the "grandaddy" of non-stick plastics, PTFE) is that they don't bond. Their innate low energy state makes them a bastard to stick to anything, even to themselves, without very special glues (3M DP8005, for example). Surface treating makes them bondable using normal materials.

Given that people have been successfully bonding surface-treated low-energy sidewalls with PU glues, I wouldn't worry about bonding bases with the same glue.

What I do worry about is the durability of GRP layups made with foaming PU glues. After all, what's where the "pop" of your ski / board is coming from. On the other hand, it's probably not gonna be *much* worse than Rossi's infamous foam core race boards of the '90s.

I guess that pressing is gonna be an issue as well, given the foaming action of PU glue whilst it polymerises. Dunno if it's gonna work with a vac bag setup.

It's an interesting exercise, though, and I'm *very* tempted to try.

MontuckyMadman · Post by **MontuckyMadman** » Sun Mar 06, 2011 11:45 pm

I know nothing but i would not consider that to be a good aetup for a compression molding application.
just what i thought initially.

skidesmond · Post by **skidesmond** » Mon Mar 07, 2011 5:12 am

Tufty - I was thinking that in the back of my mind also. It does seem to bond the materials together, but will it perform like and epoxy/FG layup?? My guess is probably not as well. So why bother? Well....

1 - just to try it and see how well it works.
2 - Toying with the idea of a "Better" wood ski. After I made the "Going Old School" ski, gorilla glue worked great at bonding the layers of wood veneers. It was more of an "ah-ha" moment to use gorilla glue, after the epoxy failed. Not bashing epoxy, it failed because of user error. I didn't mix it well and I didn't warm it thoroughly either.
3 - With Gorilla glue it takes only a couple hours to set up, don't need heat, shorter cure time. No mixing. Use less.

And I guess another driving force is the "Going Old School" ski looks great but since I put a wood base on it it skied like crap. And really wish I used P-tex. So I'm betting that I can make another wood ski w/ a P-tex base using gorilla glue, perhaps replacing 1 layer of veneer with F/G.

4 - And it's fun to experiment!

Eirik Hanes · Post by **Eirik Hanes** » Mon Mar 07, 2011 5:53 am

Edit: seem like this post did't work the first time...

Before building a pair of skis with this I would look more into how the properties of polyurethane changes with temperature. After a quick google search I found this:

http://www.adhesivestoolkit.com/Docu-Da ... C(A)23.pdf

Looking at figure 1 page 6, it sems that this polyurethane compound (3m dp 609 ) goes towards a glassy state at 0 C. As the author writes: "At the lowest temperature 0 °C the adhesive is approaching a glassy state. The modulus has increased significantly whilst the strain to failure has decreased"

This also means that that using this type of polyurethane will make a ski with changing flex, that will probably break at low temperatures.

I am not sayin that it's not possible to use polyurethane, just that i would carefully investigate the properties of the specific polyurethane adhesive chosen.

Also remember, if the modulus of the polyurethane and the fiber content obtained changes significantly from what we usually have with epoxy resins, this will affect the ski flex.

After reading this paper, I would like to see how the curves for the epoxy i am using are! And, we are using polyurethane to glue steel edges and sidewall, maybe its not such a good idea after all?

skidesmond · Post by **skidesmond** » Mon Mar 07, 2011 2:24 pm

Eirik - I saw your post about the polyu glue paper. Thanks for sharing. After I read it I put my samples in the freezer for about an hour. Took them and tried to flex them. Of course is was harder to flex because they were frozen. When I really forced it the wood veneer snapped. And I flexed it far more than a ski would flex, under normal conditions. The FG, glue, P-tex did not peel away.

I know this is a pretty informal/unscientific experiment. I really should make 2 control pieces. One using epoxy, the other glue, run tests and then document the results. Ugh, another task for the To-Do list.

Eirik Hanes · Post by **Eirik Hanes** » Mon Mar 07, 2011 3:08 pm

great! I see that in the 3M brochure they rate the adhesive from -50C to 80, so i guess it's not that "glassy". I am very interested in seeing a prototype ski made with polyurethane!

skidesmond · Post by **skidesmond** » Thu Mar 10, 2011 4:39 am

Here's the ski where I did use Gorilla glue. But it doesn't have FG or P-Tex base.

http://www.skibuilders.com/phpBB2/viewtopic.php?t=2845

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